Answer:
12.26%
Explanation:
MM K = 39.1 g/mol
MM K2CO3 . 10H2O = 2x39.1 + 12.01 + 3 x 15.99 + 10 x 18.02= 318.38 g/mol
% by weight = (MM K/MM K2CO3.10H2O ) x 100= (39.1/318.8) x 100=12.26 %
<h2>Definition:</h2>
Chemistry is the study of matter, it's properties, how and why substances combine or separate to form other substances, and how substances interact with energy. Chemistry is one of the physical sciences that help us to describe our world.
<h2>sentence examples:</h2>
•chemistry is a little hard.
•chemistry is fun to do!
<h2>synonyms:</h2>
•system
•organizing
•structure
•plan
•standard
•assembly
•design
•formation
•pattern
•method
•construction
<h2>antonyms:</h2>
•imbalance
•disproportion
•disorganizing
<h2>Origin:</h2>
Chemistry comes from Arabic word al-Kimia which means the art of transformation. Chemistry began as the study of alchemy.
If an emergency vehicle passes you in traffic, just as it passes you the pitch of the siren changes as it approaches, the siren’s pitch sounds higher than when it is moving away from you.the frequency increases as the siren is moving toward you, and decreases as it is moving away, is correct
This change is a common physical demonstration of the Doppler effect.
<h3>What is Doppler effect ?</h3>
This effect refers to the increase in the frequency of sound, as the source and observer move toward (or away from) each other.
The effect causes the sudden change in pitch noticeable in a passing siren.
Hence Option (B) i.e, the frequency increases as the siren is moving toward you, and decreases as it is moving away, is correct
Learn more about Doppler' effect here ;
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Density is given by mass divided by the volume of a substance.
In this case the mass is 0.794 g and the volume is 0.82 cm ×1.45 cm ×1.25 cm = 1.48625 cm³.
Therefore, density = 0.794/ 1.48625
= 0.5342 g/cm³
Thus, the density of lithium metal is 0.5342 g/cm³
The partial pressure<span> of </span>water<span> in the mixture, P</span>water<span>, is the equilibrium </span>vapour pressure<span> of </span>water<span> at the temperature specified. At 298 K, from the data at the beginning of the questions section, P</span>water<span> = 3.17 kPa. Using the Ideal Gas Equation, the number of moles of N</span>2<span> can be calculated.</span>
